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| United States Patent |
5,207,871
|
|
Murphy
, et al.
|
May 4, 1993
|
Process for making transparent paper using a UV curable compositions of
maleate, vinyl monomer and an allyl compound
Abstract
A composition which is cured upon exposure to ultraviolet light in the
absence of solvent is disclosed. The liquid composition is prepared by
combining a liquid maleate polyester and at least one of a vinyl compound
and an allyl functional compound. A photoinitiator is then added to the
polymerizable liquid composition. A substrate is impregnated with the
polymerizable liquid composition and exposed to actinic energy of a
sufficient dosage for a sufficient amount of time to polymerize the
composition to a sufficient degree to impart useful properties to the
substrate. The composition can be used as a binder for fiberglass
insulation, in the manufacture of transparent or semi-transparent paper
and to manufacture paper for use in photocopy machines.
| Inventors:
|
Murphy; Edward J. (Arlington Heights, IL);
Zahora; Edward P. (Naperville, IL);
Shama; Sami A. (Hoffman Estates, IL)
|
| Assignee:
|
DSM N.V. (NL)
|
| Appl. No.:
|
714856 |
| Filed:
|
June 13, 1991 |
| Current U.S. Class: |
162/164.7; 162/168.7; 162/192; 522/46 |
| Intern'l Class: |
D21H 019/28 |
| Field of Search: |
162/192,164.7,168.7,164.1
427/379,53.1
428/264,481
522/46,8
|
References Cited
U.S. Patent Documents
| 4237185 | Dec., 1980 | Lombardi et al. | 522/89.
|
| 4761435 | Aug., 1988 | Murphy et al. | 522/46.
|
Primary Examiner: Jones; W. Gary
Assistant Examiner: Nguyen; Dean
Attorney, Agent or Firm: Dressler, Goldsmith, Shore, Sutker and Milnamow, Ltd.
Claims
What is claimed is:
1. A process for making a transparent paper comprising:
impregnating paper stock with a liquid mixture consisting essentially of a
liquid maleate polyester with a photoinitiator and at least one of a vinyl
monomer, oligomer or polymer, and an allyl functional compound; and
polymerizing the liquid mixture in situ on the paper stock by exposing the
impregnated paper stock to ultraviolet light.
2. The process according to claim 1 wherein the maleate polyester has at
least two maleate functional groups and wherein the molecular weight of
the maleate polyester is about 400 to about 5000.
3. The process according to claim 2 wherein the maleate polyester is a
substantially linear molecule having two ends with one maleate functional
group at each end of the molecule and wherein the molecular weight of the
maleate polyester is about 400 to about 1000.
4. The process according to claim 1 wherein the allyl functional compound
is a triallyl cyanuate.
5. The process according to claim 4 wherein the triallyl cyanurate is
2,4,6-triallyloxy-1,3,5-triazine.
6. The process according to claim 1 wherein the photoinitiator is a ketonic
photoinitiator added in an amount of about 2 to about 10 parts by weight
of the liquid mixture.
7. The process according to claim 6 wherein the liquid mixture is
polymerized by exposing the impregnated paper stock to a dosage of
ultraviolet radiation in the range of about 0.1 joule to about 2 joules
per square centimeter of impregnated paper stock.
8. The process according to claim 6 wherein the dosage of ultraviolet
radiation is in the range of about 0.2 joule to about 1 joule per square
centimeter of impregnated paper stock.
9. The process according to claim 1 wherein the mole ratio of the liquid
maleate polyester, the vinyl monomer, oligomer or polymer and the allyl
functional compound in the liquid mixture is about 1:2:1 to about 2:1:2
wherein the liquid maleate polyester, the vinyl monomer, oligomer or
polymer and the allyl functional compound are represented in any order in
the ratio.
10. The process according to claim 1 wherein about 0.002 gram to about 0.01
gram of the liquid mixture is impregnated into the paper stock per square
inch thereof.
11. The process according to claim 1 wherein about 0.004 gram to about
0.008 gram of the liquid mixture is impregnated into the paper stock per
square inch thereof.
Description
FIELD OF THE INVENTION
The invention is directed to a composition which is cured upon exposure to
ultraviolet light in the absence of solvent.
BACKGROUND
There are a multitude of compositions which are applied to an article in
liquid form and, when cured, polymerize to provide the article with a
protective coating or otherwise impart useful properties to the article.
Many of these compositions are viscous and require the addition of an
organic solvent to reduce their viscosity so that the compositions can be
evenly and effectively applied to the article. The organic solvents
typically evaporate when the composition is cured, however, especially
when heat is used to cure the compositions. The fumes from the organic
solvents must then be recovered. Recovery and disposal of these fumes is
expensive.
Polymerizable compositions that have a low viscosity without the addition
of an organic solvent are obviously preferable in those applications when
low viscosity is a desirable characteristic of the composition. The
compositions are easily and accurately applied, and no difficulty or
expense in controlling solvent fumes is encountered. Polymerizable
compositions which can be cured using a more energy efficient curing
mechanism, such as ultraviolet light, are also desirable. A polymerizable
composition which can be cured by a solventless ultraviolet light cure
process can be applied economically and accurately and, when cured,
imparts useful properties to an article.
SUMMARY OF THE INVENTION
A liquid maleate polyester and at least one of a liquid vinyl monomer,
oligomer or polymer and an allyl functional compound are combined to form
a polymerizable liquid mixture.
A photoinitiator is then added to the liquid mixture. The liquid maleate
polyester in the polymerizable liquid preferably has at least two maleate
functional groups. The maleate polyester is preferably a substantially
linear polyester that is end-capped with maleate functional groups, one
maleate functional group being at each end of the maleate-functional
oligomer. Maleate polyesters suitable for use in the coating process and
composition of the present invention have a molecular weight of about 400
to about 5000, preferably about 400 to about 1000.
The liquid maleate polyester is combined with at least one of a vinyl ether
or vinyl ester compound and an allyl functional compound, preferably a
triallyl cyanurate. Compositions containing the three components are
combined in amounts so that the mole ratio is in the range of about 1:2:1
to about 2:1:2, wherein the maleate polyester, the multifunctional vinyl
compound and the allyl functional compound are represented in any order in
the ratio. Compositions containing only the maleate polyester and the
allyl functional compound are combined in amounts sufficient to produce a
mole ratio of maleate polyester to allyl functional compound in the range
of about 1:3 to about 2:3 and compositions containing only the maleate
polyester and the vinyl functional compound are combined in amounts
sufficient to produce a mole ratio of maleate polyester to vinyl
functional component in the range of about 1.2:1 to about 1:1.2.
The photoinitiator that is added to the liquid monomer mixture is
preferably a ketonic photoinitiator. About 2 to about 10 parts by weight
of the ketonic photoinitiator are added to the liquid monomer mixture to
provide the ultraviolet curable liquid mixture that is applied to the
paper stock.
The liquid mixture can be applied onto a variety of substrates and cured
according to the disclosed process to provide a variety of useful
articles. For example, the mixture can be applied onto a commercial
drafting paper stock and cured thereon to produce semi-transparent paper
used for architectural drawings and as a transparent window for envelopes.
Filter paper is produced by applying the mixture to corrugated paper and
then curing the mixture thereon. The liquid mixture can also be used to
water proof and/or strengthen paper and cardboard products according to
the disclosed process. The liquid mixture can also be used as binder in
fiberglass insulation by applying the liquid mixture to a fiberglass web
and exposing the resulting coated web to ultraviolet light. The liquid
mixture can also be used to manufacture paper suited for use in photocopy
machines. The photocopy paper that results does not smoke or emit fumes as
does paper currently used in photocopy machines. The liquid mixture can
also be applied to glass fiber or pourous plastic substrates and then
cured thereon to impart useful properties to these substrates.
The liquid mixture is used to impregnate a substrate such as paper stock,
fiberglass insulation, and the like. The substrate is preferably porous.
The substrate can be impregnated by any known means that is suitable for
introducing liquid into a porous substrate.
The impregnated substrate is then exposed to actinic energy whereupon the
photoinitiator initiates polymerization of the mixture A dosage of
ultraviolet light of about 0.1 joule/cm.sup.2 to about 2 joules/cm.sup.2,
preferably about 0.2 joule/cm.sup.2 to about 1 joule/cm.sup.2 is
sufficient to polymerize the liquid mixture. Polymerization of the liquid
mixture cures the impregnated substrate resulting in a substrate with
desirable properties.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The composition of the present invention is applied to a substrate such as
commercial drafting paper stock, fiberglass webs, photocopy paper stock,
or other suitable porous substrates and polymerized to provide useful
properties to the substrate. The composition, when applied to commercial
drafting paper stock and cured, provides a degree of transparency to the
paper. The composition, when applied to photocopy paper stock and cured,
provides photocopy paper which does not smoke or give off fumes when used.
The composition is also useful as a binder in fiberglass insulation. The
composition is applied to a fibrous fiberglass web and cured in situ.
The composition is a liquid mixture of a maleate functional polyester resin
and at least one of a vinyl ether or ester compound and an allyl
functional compound such as a triallyl cyanurate. The composition also
contains a ketonic photoinitiator that can be added to the mixture at any
time prior to use. The polymerizable liquid mixture is impregnated into
commercial drafting paper stock according to the process disclosed herein
to produce transparent or semi-transparent papers.
Most of the commercially available maleate polyesters are suitable for use
in the composition and process of the present invention. Maleate
polyesters with a molecular weight of about 400 to about 5000 are
particularly suitable. Maleate polyesters with a molecular weight of about
400 to about 1000 are preferred. The polyesters are maleate functional,
i.e. the only reactive groups on the polymer are maleate groups. The
preferred maleate-functional polyesters have a functionality of about 2,
which means that each molecule has two maleate functional groups thereon.
A single maleate functional group is preferably at each of the two ends of
the polyester molecule, so that the polyester molecule is end-capped with
the maleate functional groups.
A maleate polyester preferred for use in the composition of the present
invention is typically manufactured by a sequential reaction. Initially,
equimolar amounts of maleic anhydride and butyl carbitol are reacted. The
reaction preferably takes place at an elevated temperature in a nitrogen
atmosphere, but at a temperature that is less than 110.degree. C. The
product from this reaction is then reacted with a reactive diol such as
1,5-pentanediol. The sequential reaction takes place in a xylene medium at
a temperature of about 140.degree. C. to about 190.degree. C. and at
ambient pressure.
Other reactive diols can be utilized such as aliphatic polyhydric alcohols
that contain 2 to 10 carbon atoms, more preferably 3 to about 6 carbon
atoms, and are illustrated by ethylene glycol, butylene glycol, ester
diol, 1,6-hexane diol, glycerol, trimethylol propane, pentaerythritol, and
sorbitol. Trimethylol propane is a particularly preferred reactive diol.
Vinyl ethers suitable for use in the present invention can be represented
by the following general Formula I:
##STR1##
wherein R.sup.e, R.sup.f, R.sup.g, R.sup.h and R.sup.i are each
independently selected from the group of hydrogen and lower alkyl groups
containing 1 to 4 carbon atoms; R.sup.e or R.sup.f and R.sup.g joined
together can be part of a ring structure; R.sup.e or R.sup.f and R.sup.h
or R.sup.i joined together can be part of a ring structure; and R.sup.g
and R.sup.h or R.sup.i joined together can be part of a ring structure;
R.sup.j is an aromatic or aliphatic group that is reactive only at the
site(s) where a vinyl ether containing radical is bound; x is 0 or 1; and
n is equal to 1 to 10, preferably 1 to 4, provided that n is less than or
equal to the number of reactive sites of R.sup.j.
R.sup.j can contain heteroatoms, i.e., atoms other than carbon atoms, such
as oxygen, nitrogen, sulfur, silicon, phosphorus, and mixtures of
heteroatoms alone or in combination with carbon atoms. R.sup.j can contain
1 to about 20, preferably 1 to about 10, atoms. R.sup.j is preferably a
straight or branched carbon containing group containing 1 to about 8, more
preferably 1 to about 4, carbon atoms and can preferably contain oxygen
atoms.
Representative of vinyl ethers of Formula I are dihydropyran and dimethyl
benzene divinyl ether.
Preferred vinyl ethers for use in the transvinylation reaction can be
represented by the following general Formula II:
(CH.sub.2 .dbd.CH--O--CH.sub.2).sub.n R.sup.k (II)
wherein R.sup.k is an aliphatic group that is reactive only at the site(s)
where a vinyl ether containing radical is bound and n is equal to 1 to 4.
R.sup.k contains at least one carbon atom and can contain heteroatoms and
mixtures of heteroatoms. Preferably, R.sup.k contains 1 to about 4 carbon
atoms and can contain oxygen atoms.
Vinyl ethers having the structure of Formula II are illustrated by divinyl
ethers, such as 1,4-butane diol divinyl ether, 1,6-hexane diol divinyl
ether, and triethylene glycol divinyl ether. Polyvinyl ethers of higher
functionality are illustrated by trimethylol propane trivinyl ether and
pentaerythritol tetravinyl ether.
Illustrative monovinyl ethers having the structure of Formula II are ethyl
vinyl ether, methyl vinyl ether, n-butyl vinyl ether, phenyl vinyl ether
and the like.
The vinyl monomer is preferably either a vinyl ether or a vinyl ester that
has more than one vinyl functional group per molecule. An example of a
suitable multifunctional vinyl compound useful in the present invention is
the divinyl ether of triethylene glycol represented by Formula III:
CH.sub.2 .dbd.CHO(CH.sub.2 CH.sub.2 O).sub.3 CH.dbd.CH.sub.2 (III)
which can be commercially obtained as DVE-3 from the GAF Corporation or
1,4-cyclohexanedimethanol divinyl ether.
Suitable vinyl functional esters are Vectomer 4010 and 4020 which can be
commercially obtained from Allied-Signal, Inc. Vectomer 4010 is an
isopthalate ester of hydroxy butyl vinyl ether that has a molecular weight
of 362 and Vectomer 4020 is a glutarate ester of 1,4-cyclohexanedimethanol
divinyl ether that has a molecular weight of 436.
Other suitable vinyl ethers include the vinyl ether aliphatic and aromatic
oligomers that can be commercially obtained as Vectomer 2010, 2015 and
2020 from Allied-Signal, Inc.
Examples of allylic monomers suitable for use in the present invention
include triallyl cyanurates, a specific example of which is
2,4,6-triallyloxy-1,3,5-triazine. This compound can be commercially
obtained as CYLINK TAC from American Cyanamid Co. Other suitable allylic
compounds include diallyl phthalate and triallyl trimellitate.
When the maleate polyester, multifunctional vinyl monomer and allyl
functional compound are present in the liquid mixture, the mole ratio of
any two components of the mixture is about 2:1 to about 1:2. Overall mole
ratios of the three components in the mixture are about 1:2:1 to about
2:1:2 wherein the maleate polyester, the multifunctional vinyl monomer and
the allyl functional compound are represented in the ratio in any order.
When only the maleate and the allyl functional compounds are present in the
liquid mixture the mole ratio of maleate to allyl functional compound is
in the range of about 1:3 to about 2:3. When only the maleate and the
vinyl ether are present in the composition, the mole ratio of maleate to
vinyl ether is in the range of about 1.2:1 to about 1:1.2, preferably
about 1:1.
The maleate polyester is then polymerized with the vinyl and/or allyl
compound by radical-initiated polymerization.
A photoinitiator which initiates radiation polymerization upon exposure of
the polymerizable liquid mixture to actinic energy such as light in or
near the ultraviolet and visible ranges, e.g., light having a wavelength
of about 200 to about 600 nanometers, is added to the liquid mixture.
Suitable photoinitiators are ketonic, and can be aromatic, such as
benzophenone. Darocur 1173 is a suitable benzyl ketal-based photoinitiator
commercially available from EM Industries and contains
2-hydroxy-2-methyl-1-phenylpropan-1-one as the active ingredient. An aryl
ketone photoinitiator that contains hydroxycyclohexylphenyl ketone as the
active ingredient is also suitable. This aryl ketone photoinitiator is
commercially available as Irgacure 184 from the Ciba Geigy Corp. Acyl
phosphine oxides such as 2,4,6-trimethylbenzoyl diphenyl phosphine oxide
available as Lucerin TPO from BASF can also be utilized. UVI 6990 or UVI
6974, cationic photoinitiators can also be used in the polymerizable
compositions disclosed herein to promote polymerization.
At least one photoinitiator is present in an amount of about 1 to about 10
weight percent in the liquid mixture based on the total weight of the
liquid mixture.
When it is desired to manufacture transparetized paper, the polymerizable
liquid mixture is applied to standard commercial drafting paper stock
using wire wound drawdown bars or any other equivalent method as would be
recognized by one skilled in the art to impregnate the paper stock with
the polymerizable liquid mixture.
The amount of the polymerizable liquid mixture used to impregnate the paper
stock controls the degree to which the paper, when cured, is transparent.
The viscosity of the polymerizable mixture enables it to penetrate the
paper stock rapidly and uniformly, which provides a paper which is
transparent to a uniform degree. This is particularly useful in
applications such as architectural drawings, where the degree and
uniformity of transparency are product specifications.
The paper stock is impregnated with about 0.002 gram to about 0.01 gram of
the polymerizable liquid per square inch for a standard thickness paper.
Preferably about 0.004 gram to about 0.008 gram of liquid mixture is used
per square inch to impregnate the paper stock. Most preferably, about
0.005 gram of the polymerizable mixture is applied per square inch of the
paper stock. For thicker papers, a greater amount of the liquid mixture
must be impregnated per square inch of the paper stock to achieve an
equivalent degree of transparency.
The liquid mixture has a viscosity of about 10 cps to about 500 cps,
preferably about 10 cps to about 100 cps. Due to the low viscosity of the
liquid mixture, the paper is impregnated with the liquid mixture very
quickly, i.e., less than about 180 seconds, preferably less than about 60
seconds. The impregnation is usually carried out at room temperature, but
may be accelerated by exposing the coated paper to mild convection heating
at temperatures in the range of about 130.degree. F. to about 250.degree.
F. Alternatively, impregnation can be accelerated by mildly heating the
liquid as it is applied to temperatures in the range of about 100.degree.
F. to about 160.degree. F.
The impregnated paper stock is then cured using a standard ultraviolet
curing unit. The paper stock is cured by polymerizing the mixture used to
impregnate the paper stock. The liquid mixture is polymerized by exposure
to ultraviolet light. A suitable ultraviolet curing unit can be obtained
from Fusion Systems of Rockville, Md. The amount of ultraviolet radiation
sufficient to polymerize the liquid mixture used to impregnate paper stock
and, thus, cure the paper stock, is about 0.1 joule/cm.sup.2 to about 2
joules/cm.sup.2. Preferably, the amount of ultraviolet radiation
sufficient to polymerize the liquid mixture used to impregnate the paper
stock is about 0.2 joule/cm.sup.2 to about 1 joule/cm.sup.2.
The present invention is illustrated by the following representative
examples.
EXAMPLE 1
A maleate polyester was prepared by reacting maleic anhydride (1 mole) with
butyl carbitol (1 mole). The reaction product was then reacted with
1,5-pentanediol (0.5 mole). A resinous liquid polyester end-capped with
maleate functional groups, one on each end, resulted. The theoretical
molecular weight of the resinous polyester was about 588.
The resinous liquid polyester was combined into separate liquid mixtures,
as enumerated in Table 1 hereinbelow. The resinous liquid polyester is
designated as olig. 20201U7 in Table 1.
TABLE 1
__________________________________________________________________________
Composition 1 2 3 4 5 6 7 8 9
__________________________________________________________________________
Olig. 20201U7 66 73.3
68.06
75.6
64 67 69.2
74 51
Triallyl Cyanurate
28 20.7
28.8
21.35
36 -- -- -- 14
Divinyl Ether -- -- -- -- -- -- -- 26 35
Darocur 1173 5.94
5.94
3 2.99
6 4.94
4.94
6 6
FC 430 0.01
0.01
0.01
0.01
0.01
0.01
0.01
-- --
BHT 0.05
0.05
0.05
0.05
0.05
0.05
-- --
Diallyl phthalate
-- -- -- -- -- 28 -- -- --
Triallyl trimellitate
-- -- -- -- -- -- 25.8
-- --
Maleate/allyl molar ratio
1:1
2:3
1:1
2:3
1:3
2:3 2:3
Minimum Cure Dose (j/cm.sup.2)
1 1.5
1.5
1.5
1.5
>2 2 0.5
0.5
Odor during cure
mild
mild
mild
mild
mild
mild
mild
mild
mild
Cured film appearance
clear
clear
clear
clear
clear
clear
clear
clear
clear
__________________________________________________________________________
All compositions were applied to standard drafting paper stock using wire
wound drawdown bars. About 0.005 gram of each of the compositions were
applied per square inch of paper stock. While all compositions were
suitable, Composition 9, which impregnated the paper stock in about 45
seconds, showed the highest impregnation speed.
Several samples of paper stock such as Crane and Esleeck Vellum, 15.5 lb.
and 17.5 lb. weight, were impregnated with each of the compositions
described in Table 1. These samples were then exposed to ultraviolet light
to polymerize the liquid mixture which was used to impregnate the samples.
A standard ultraviolet light cure unit was used. The cure unit was
obtained from Fusion Systems of Rockville, Md. The samples of impregnated
paper stock were exposed to varying dosages of ultraviolet light as set
forth in Table 2 below. The samples were then weighed and extracted at
room temperature in an organic solvent, methyl ethyl ketone, for 15
minutes. The samples were then dried and reweighed. The percent by weight
extractable components of compositions 8 and 9 were markedly different
after exposure to identical amounts of ultraviolet light. The difference
was especially noticeable in the samples which were exposed to lower
dosages of ultraviolet light (0.2 to 0.8 joule/cm.sup.2). These results
are reported in Table 2 below.
TABLE 2
______________________________________
EXTRACTABLE AMOUNTS OF POLYMERIZED MIX-
TURES AT VARIOUS CURE DOSAGES
Ultraviolet Light
% Extractables (MEK)
Dosage Composition
Composition
(joules/cm.sup.2)
8 9
______________________________________
0.2 8 2
0.4 3.5 1.5
0.6 2 1.2
0.8 1.5 1
1 1 1
______________________________________
Table 2 demonstrates that composition 9 polymerized more completely at
lower dosages of ultraviolet light than composition 8, which did not
contain triallyl cyanurate.
Additional compositions of the present invention were prepared and
evaluated by conventional procedures.
In Table 3 below, various compositions containing diethyl maleate polyester
and an isophthalate ester of hydroxybutyl vinyl ether (Vectomer 4010)
either alone or in combination with another vinyl ether oligomer (Vectomer
2015) were prepared. The data in Table 3 show that a mole ratio of diethyl
maleate to vinyl ether of about 1:1 is optimal.
TABLE 3
__________________________________________________________________________
V3
Composition V1 V2 (Control)
V4 V5 V6
__________________________________________________________________________
Vectomer 2015 (VE)
-- 6.5 -- -- -- --
Vectomer 4010 (VE)
49.73
27.82
98.94
49.73
49.73
49.73
Diethyl Maleate
47.21
62.62
-- 47.21
47.21
47.21
Darocur 1173 3 3 -- 3 -- 3
FC 430 0.01
0.01
0.01 0.01
0.01
0.01
BHT 0.05
0.05
0.05 0.05
0.05
0.05
UVI 6974 -- -- 1 0.2 -- 0.02
Lucirin TPO -- -- -- -- 2 1
Minimum Cure Dose (j/sq.cm)
1 >2 1 >2 >1 0.5
Odor during cure
+++ +++ ++ +++ ++ +++
Cured film appearance
clear
clear
dark dark
clear
clear
MEK extractables at cure dose
-- -- -- -- 64% 19%
Maleate/VE molor ratio
1.03:1
2.4:1 1.03:1
1.03:1
1.03:1
__________________________________________________________________________
In Table 4 below, other compositions containing Vectomer 4010, DVE-3 and
diethyl maleate polyester were prepared. While the most rupture resistant
cured film is obtained using UVI 6974 photoinitiator, a strong odor is
produced and a brown film results. Of the diethyl maleate
polyester-containing films in Table 4, the film with the 1:1 vinyl ether
to maleate ratio (composition V8) was the most rupture resistant.
TABLE 4
______________________________________
V7 V8 V9 V10 V11
______________________________________
Vectomer 4010
80 37.32 39.31 35.29 99.4
DVE-3 19.3 9.33 9.83 8.82 --
Diethyl -- 51.35 48.86 53.89 --
Maleate
Darocur 1173
-- 3 3 3 --
Lucirin TPO
-- 1 1 1 --
UVI 6974 0.7 -- -- -- 0.6
Vinyl ether/
-- 1:1 1.11:1
1:1.11
--
maleate ratio
Odor during
++++ ++ ++ ++ ++++
cure
Film color
Brown Clear Clear Clear Brown
MEK rupture
time
@0.5 J >15 min. uncured un- un- >15 min.
cured cured
@1.0 J >15 min. 12 sec. 8 sec.
8 sec.
>15 min.
@1.5 J >15 min. 137 sec. 80 sec.
9 sec.
>15 min.
______________________________________
In Table 5 below, other compositions containing Vectomer 4010 and a maleate
oligomer were prepared. All of the compositions were cured by exposing
them to a radiation dosage of 0.5 J/sq.cm. While compositions V12, V13 and
V14 all had good characteristics, V13 had the least odor.
TABLE 5
______________________________________
V12 V13 V14 V15
______________________________________
Vectomer 4010
51.3 38 39 40.7
Oligomer 20201U7
-- 61.9 42.5 50
Diethyl Maleate
48.7 -- 18.5 9.4
FC430 0.01 0.01 0.01 0.01
Darocur 1173 3 3 3 3
Lucirin TPO 3 3 3 3
Maleate to VE
1:1 1:1 1.2:1 1:1
Molar ratio
Liquid
Color Light Yellow
Yellow Yellow Yellow
Appearance clear clear clear clear
4.7% 4.3% 2.4% 12.0%
______________________________________
Additional compositions were prepared using the ingredients as set forth in
Table 6 below.
TABLE 6
______________________________________
V16 V17 V18 V19
______________________________________
Oligomer 20201U7
64.00 60.34 58.4 48.1
Triallyl Cyanurate
36.00 33.94 -- 13.2
Vectomer 4010 -- -- 35.9 --
DVE-3 -- -- -- 33
FC 430 0.01 0.01 0.01 0.01
BHT 0.05 0.05 0.05 --
Darocur 1173 3.00 2.83 2.82 1.9
Lucirin TPO 3.00 2.83 2.82 3.8
Phenothiazine -- -- -- 0.01
______________________________________
EXAMPLE 2
The compositions set forth in Tables 1-6 above were tested on a paper
transparentization line at a speed of up to 150 ft/min. with complete cure
(under two 400 watt/inch medium pressure UV lamps). A complete paper roll
was first coated at speeds of up to 500 ft/min. The roll was allowed to
reach saturation equilibrium, which took about thirty minutes. The paper
was then passed under the UV lamps as mentioned above at a rate of 150
feet per minute. The resulting paper was uniformly saturated and showed no
curling. Pencil markings were easily erased from the paper. The paper was
used for reproducing drawings in the diazo blueprint process successfully.
When the transparentized paper of the present invention was used in the
diazo blue print process instead of conventional paper, a faster machine
speed was required.
The compositions of the present invention can be completely polymerized
using UV doses as low as 0.2 to 0.5 joule/cm.sup.2. The compositions of
the present invention thus enable transparent papers to be produced at a
lower energy cost Since the compositions of the present invention also
have lower viscosities, these compositions impregnate paper stock faster
than prior art compositions. Thus, a faster, more energy efficient process
for producing transparent paper is available by using the polymerizable
liquid compositions disclosed herein to saturate the paper stock used in
the process. Finally, the process disclosed herein does not require the
use of an organic solvent, and, hence, the problems associated with
handling solvents are eliminated by using the process disclosed herein.
All of the composition enumerated in Tables 1 through 6 have a low
viscosity prior to being cured. The compositions cure rapidly when exposed
to ultraviolet light and are only mildly odorous. The compositions
saturate paper stock rapidly and are therefore suited for use in the
process for transparentizing papers disclosed herein. The cured
compositions exhibit good mechanical properties (e.g. flexibility,
strength, etc.) and retain these properties over time. The compositions
are very versatile. By changing the mole ratio of the polymerizable
components in the composition, the composition can be tailored for use in
a particular application.
The amount of liquid mixture impregnated into the paper stock determines
the degree to which the resulting paper is transparent. The composition is
then polymerized in situ on the paper stock by exposing the impregnated
paper stock to ultraviolet light. The paper, thus cured, is at least
semi-transparent.
The compositions of the present invention are also useful as a binder for
fiberglass insulation. The compositions of the present invention are safer
and more economical to use than the binders currently used. Binders
currently used in fiberglass insulation contain urea-formaldehyde and thus
exude toxic fumes when cured. The compositions of the present invention
are solventless and therefore do not give off fumes when cured. A large
cure oven is required to cure these urea-formaldehyde containing binders.
Since the compositions of the present invention can be cured by exposing
them to ultraviolet light, a cure oven is not required, making the curing
process more energy efficient.
The compositions disclosed in Tables 1-6, particularly compositions V17-V19
in Table 6, can also be used to saturate paper for use in photocopying
machines. Such saturated paper stock, when cured, can be used in
photocopying machines without producing smoke or odor, such as that
produced by conventional paper used in photocopying machines.
The examples and illustrations discussed herein are intended to highlight
the more general concepts disclosed. The scope of the invention is defined
by the claims appended hereto and is not to be construed as limited by the
examples or detailed discussion set forth herein.
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